Armor & Mobility

AUG 2017

Military magazines in the United States and Canada, covering Armor and Mobility, focuses on tactical vehicles, C4ISR, Special Operations Forces, latest soldier equipment, shelters, and key DoD programs

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Allen. "The user community asked us to examine conditions where the
distance between elements could be shortened."
In 2014, YPG testers undertook an ambitious two-week study
of the life cycle of these vortices, using a small Twin Otter aircraft
equipped with Light Detection and Ranging (LIDAR), a surveying
technology that measures reflections of particulates in the air by
illuminating an area of regard with eye safe laser light. The Twin Otter
was used to fly above a massive C-17, scanning the wake it left behind.
The testers flew missions across all hours of the day and night, during
different weather conditions and over different terrain features.
"Our intention was to go into the field to capture vortex data in
operationally representative scenarios," said Allen. "We had to first
understand the mechanics of the vortices and how they behaved in
the field."
The LIDAR used to scan the air disturbances caused by the vortices
is sensitive enough to pick up everything within the scanned area,
including wind, thermals, and ground effects unrelated to the C-17
passing through the area. To be useful, this data had to be separated
out from the effects of the C-17 in time and space, which was quite a
challenge.
"We had to develop a mathematical algorithm that not only
detected the vortex within all the rest of this noise, but separated it
out," explained Allen. "That took several months: we then had to decide
which factors about the vortex were most important."
Moving Data Implementation Forward
Once the testers accomplished this feat, they compared the
real-world data with predictions that had been made in computer
simulations prior to testing. Going forward, YPG testers hope to
conduct similar testing in different natural environments. Allen says
the information learned in this testing is beneficial to other air drop
activities, both at YPG and elsewhere.
"It gives YPG a lot of new capabilities as far as modeling,
simulation as well as test methodology and new procedures for
collecting wing tip vortices," said Allen. "The results of these studies
are relevant to the entire aviation industry: there are LIDAR systems
at large airports that look at the dissipation of vortices to govern their
takeoff times for aircraft."
Data collection techniques developed for this study may have
far reaching impacts on how wing tip vortices of both military and
commercial aircraft may be studied in the future.
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To study the vortices caused by cargo planes, U.S. Army Yuma Proving Ground testers conducted more than 150 flights across all hours of the day and night for two weeks, using a LIDAR-
equipped chase plane to characterize the aerial disturbance left in the plane's wake. The testers frequently changed their flight approaches in real time to accommodate different wind and
weather conditions. (U.S. Army Photo)
ENHANCING RE-SUPPLY LOGISTICS AIR DROP PRECISION
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